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Intermittent upwelling of asthenosphere beneath the Gregory Rift, Kenya
Author(s) -
Tatsumi Yoshiyuki,
Kimura Nobukazu,
Itaya Tetsumaru,
Koyaguchi Takehiro,
Suwa Kanenori
Publication year - 1991
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/91gl01348
Subject(s) - asthenosphere , geology , rift , upwelling , basalt , mantle (geology) , geochemistry , volcanism , lava , partial melting , lithosphere , rift zone , earth science , petrology , volcano , paleontology , oceanography , tectonics
K‐Ar dates and chemical compositions of basalts in the Gregory Rift, Kenya, demonstrate marked secular variation of lava chemistry. Two magmatic cycles characterized by incompatible element relative depletion are recognized; both occurring immediately after the peak of basaltic volcanism and coeval with both trachyte/phonolite volcanism and domal uplift of the region. These cycles may be attributed to increasing degree of partial melting of mantle source material in association with thinning of the lithosphere by thermal erosion through contact with hot upwelling asthenospheric mantle. Cyclic variation in asthenosphere upwelling may be considered an important controlling process in the evolution of the Gregory Rift.